Roller blinds

Abstract

A roller blind has a roller with axially projecting trunnions each of which engages in an elongated arcuate slot in a respective end bracket mounting the blind on a supporting structure such as window frame. One trunnion is connected to a reversible motor for winding up and lowering the blind. The trunnions each bear frictionally on an edge bounding the slot, and the blind is wound on the roller such that rotation of the roller in the direction to lower the blind causes movement, by frictional engagement, of the trunnions along the slots to bring the blind closer to the window frame, whereas winding up of the blind moves it farther away from the window frame.

I claim: 
     
       1. A roller blind comprising: (i) a pair of brackets, for mounting on a support structure each bracket including an arm with an elongated slot therein, the brackets each being such that when they are mounted on the supporting structure the slot extends in the direction away from the support structure,   (ii) a roller, to receive a screen, having a respective trunnion extending axially from each end of the roller, each said trunnion being engaged through the slot of a respective one of the brackets and bearing frictionally on an edge bounding the slot,   (iii) a screen having an end thereof secured to said roller,   (iv) reversing motor drive means connected to one of said brackets and to the roller for rotating said roller, the screen being wound onto the roller in the direction such that rotating of the roller in the direction to lower the screen causes travel of the trunnions along the respective slot to bring the screen nearer to the support structure, and rotation of the roller in the direction to raise the screen causes travel of the trunnions along the respective slot to move the screen farther away from the support structure, wherein the reversing motor drive means comprises an electric motor mounted by a pivot on said one bracket and having a drive shaft drivingly connected to the adjacent trunnion, said slot being arcuate and the axis of said pivot being concentric with the axis of said arcuate slot, said pivot providing clearance such that the respective trunnion rests by its own weight, and the weight of the roller and blind, on said edge bounding the slot.   
     
     
       2. A roller blind, as claimed in claim 1, wherein said motor drive shaft carries a worm which is meshed with a worm wheel secured on the trunnion.